Imaging system using a negative index of refraction lens

Abstract

Systems and methods for imaging a distant light source at an enhanced resolution is provided. An evanescent field generator an evanescent field generator that receives an incident electromagnetic field representing at least one distant light source and restores high spatial frequency components to the incident electromagnetic field, resulting in an evanescent field. A negative refractive index lens assembly focuses the evanescent field onto a focal plane. A photodetector assembly located in the focal plane detects the focused evanescent field as an image of the at least one distant light source.

1. An imaging system having an enhanced resolution, comprising:
 an evanescent field generator configured to receive an incident electromagnetic field representing at least one distant light source and restores high spatial frequency components to the incident electromagnetic field, resulting in an evanescent field, the evanescent field generator comprising a plate with a plurality of apertures arranged in a grid, where the diameter and effective path length of each of the plurality of apertures being selected to apply a desired transfer function to an incident electromagnetic field representing the at least one distant light source such that a first aperture of the plurality of apertures has a different effective path length than a second aperture of the plurality of apertures; 
 a negative refractive index lens assembly that focuses the evanescent field onto a focal plane; and 
 a photodetector assembly located in the focal plane that detects the focused evanescent field as an image of the at least one distant light source. 
 
     
     
       2. The system of  claim 1 , at least one of the plurality of apertures being filled with a dielectric material as to provide the selected effective path length at the at least one aperture. 
     
     
       3. The system of  claim 1 , the negative refractive index lens assembly comprising:
 a first lens that focuses the evanescent field into respective intermediate fields along a first transverse axis; and 
 a second lens that focuses the intermediate fields into a single focal point having a width less than an associated wavelength of the at least one distant light source. 
 
     
     
       4. The system of  claim 3 , wherein the first lens comprises a plate having a thin-film layer of silver with a grating aligned in a first direction and the second lens comprises a plate having a thin-film layer of silver with a grating aligned in a second direction. 
     
     
       5. The system of  claim 1 , further comprising a preconditioning lens, having a positive index of refraction that directs light from the at least one distant light source to the evanescent field generator. 
     
     
       6. A method for imaging at least one distant source of light, comprising:
 restoring high spatial frequency components to an incident electromagnetic field representing the at least one distant light source to produce an evanescent field; 
 focusing the evanescent field with a negative refractive index lens onto a focal plane, wherein focusing the evanescent field with a negative refractive index lens comprises directing the light through a first lens to focus the evanescent field into respective intermediate fields aligned longitudinally along a first transverse axis and directing the light through a second lens to focus the intermediate fields into at least one focal point having a width less than an associated wavelength of the at least one distant light source; and 
 detecting the focused evanescent field in the focal plane. 
 
     
     
       7. The method of  claim 6 , wherein restoring high spatial frequency components to an incident magnetic field comprises directing incident light from the at least one distant source of light at a mask comprising a plurality of apertures, where the diameter and effective path length of each of the plurality of apertures is selected to apply a desired transfer function to an electromagnetic field representing the at least one light source. 
     
     
       8. The system of  claim 1 , wherein the negative refractive index lens comprises a Pendry slab lens. 
     
     
       9. A spatial frequency reconstruction assembly for focusing light from a distant light source, comprising:
 a mask comprising a plurality of apertures, where the diameter and effective path length of each of the plurality of apertures is selected to apply a desired transfer function to an incident electromagnetic field representing the at least one distant light source to produce an evanescent field such that a first aperture of the plurality of apertures has a different effective path length than a second aperture of the plurality of apertures; and 
 a negative refractive index lens assembly, having at least one surface separated by an infinitesimal gap from a surface of the mask, that focuses the evanescent field to a focal plane associated with the negative refractive index lens. 
 
     
     
       10. The assembly of  claim 9 , the plurality of apertures being arranged in a rectangular grid on the mask. 
     
     
       11. The assembly of  claim 9 , at least one of the plurality of apertures being filled with a dielectric material as to provide the selected effective path length at the at least one aperture. 
     
     
       12. The assembly of  claim 9 , the negative refractive index lens assembly comprising:
 a first lens that focuses the evanescent field into respective intermediate fields along a first axis; and 
 a second lens that focuses the intermediate fields into a single focal point having a width less than an associated wavelength of the at least one distant light source. 
 
     
     
       13. An imaging system having an enhanced resolution, comprising:
 an evanescent field generator configured to receive an incident electromagnetic field representing at least one distant light source and restores high spatial frequency components to the incident electromagnetic field, resulting in an evanescent field; 
 a negative refractive index lens assembly that focuses the evanescent field onto a focal plane, the negative index of refraction lens assembly comprising a first thin-film layer of silver with a grating aligned in a first direction that focuses the evanescent field into respective intermediate fields along a first axis and a second thin-film layer of silver with a grating aligned in a second direction that focuses the intermediate fields into a single focal point having a width less than an associated wavelength of the at least one distant light source; and 
 a photodetector assembly located in the focal plane that detects the focused evanescent field as an image of the at least one distant light source.